My cousin has the penguin and I used it extensively while visiting a couple weeks ago. I only used it to make seltzer water and it's fantastic. I'm not a big soda drinker so I didn't try any of the flavors, but my guess is the energy drink will fall flat compared to redbull. The other thing is the replacement CO2 cartridges are expensive to replace. When you factor that into the price of the unit it's really not that cheap. Well, maybe for energy drinks that are $2 apiece, but not for sodas or seltzer. There's a company that makes a valve you can put on the cartridge that allows you to refill it at a paintball shop or industrial gas store at a fraction of the cost of a new cartridge. If I were to get a sodastream this is the route I'd go. http://co2doctor.com/